它们的观察值分别为 x=∑x ∑ 2∑x2 S三 n-1 ∑ ∑x,k=12 (x1-x)^,k=12它们的观察值分别为： ∑= = n i i x n x 1 1 [ ] 1 1 ( ) 1 1 1 2 2 1 2 2 ∑ ∑ = = − − − = − = n i i n i i x n x n x x n s ∑= − − = n i i x x n s 1 2 ( ) 1 1 , 1,2 " 1 1 = ∑ = = x k n a n i k k i ( ) , 1,2 " 1 1 = ∑ − = = x x k n b n i k k i